Because ssh is disabled by default, place an empty file name 'ssh' on the SD-card to enable ssh on boot

The Raspberry Pi should be unplugged from power.

Put the SD card in your Pi and connect a mouse, keyboard, Ethernet cable and monitor. Finally plug in the micro USB power supply. This action will turn on and boot your Raspberry Pi.

First time startup

The default username and password are pi and raspberry

Get IP address with local access

The Raspberry Pi image is configured with DHCP, meaning, it will get an IP Address from your router.
If you connect to your router you should see a section with 'DHCP' and see the IP Address assigned to the Raspberry Pi.
Otherwise connect the Raspberry Pi to a monitor and keyboard to gain local access.
Turn on the Raspberry Pi and the monitor and you should see the commandline interface.
Login with the default username and password (pi/raspberry) and issue the following command:

ifconfig

Using SSH to access the Raspberry Pi (Recommended)

Once you know the IP Address of the Raspberry Pi, you can use a SSH Client (Putty for example) to connect to the Raspberry Pi.
When you are using the ssh command line client in Linux or on Mac OS, you have to add the userid to the ssh command: